Modifying a data structure while iterating over it

Question

What happens when you add elements to a data structure such as a vector while iterating over it. Can I not do this?

I tried this and it breaks:

int m         


        

Answer 1

While you used vector as an example, there are other stl containers which are able to have elements pushed-back without invalidating iterators. Pushing back an element into a std::list doesn't require any re-allocation of existing elements as they aren't stored contiguously (lists instead comprise of nodes linked together by pointers to the next node), therefore iterators remain valid as the node they internally point to still resides at the same address.